![Smog covers buildings in New Delhi in this aerial photo on May 8, 2014](https://webarchive.library.unt.edu/web/20141023003951im_/http://static.guim.co.uk/sys-images/Guardian/Pix/pictures/2014/10/17/1413555771319/1490f125-8340-4075-b1b4-306d93d8127b-460x276.jpeg)
India launched an index on Friday to measure air quality across the country, which is home to some of the most polluted cities in the world.
It will measure eight major pollutants that impact respiratory health in cities with populations exceeding one million in the next five years and then gradually the rest of the country, Environment Minister Prakash Javadekar told reporters. The Air Quality Index will warn residents when pollution levels shoot past dangerous levels.
The World Health Organisation said earlier this year that the Indian capital had the worst air quality in the world, surpassing Beijing, a statement that New Delhi has vehemently disputed.
Air monitoring sensors around the landlocked Indian capital routinely register levels of small airborne particles at “hazardous” levels, especially in winter. The levels are three to four times New Delhi’s own sanctioned limit, rivalling Beijing.
Like the Chinese capital, New Delhi has gone through rapid economic development, raising living standards but also spewing out pollution.
Decades of policies that favoured economic decisions over environmental concerns have taken their toll. The numbers of cars on the roads of New Delhi have doubled in the last decade and years of booming construction has kicked up countless clouds of dust.
![Traffic moves at dusk in New Delhi, India, on 23 September 2014.](https://webarchive.library.unt.edu/web/20141023003951im_/http://static.guim.co.uk/sys-images/Guardian/Pix/pictures/2014/10/17/1413556735706/0f768a6d-373a-43eb-b19a-78481df661c3-460x276.jpeg)
Javadekar said it wouldn’t be “business as usual anymore” and the government was committed to improving air quality as part of a cleanliness drive launched by Prime Minister Narendra Modi earlier this month.
There are various ways to measure pollution, but comparisons have generally focused on the microscopic particulate matter, sometimes called black carbon or soot, which can lodge in a person’s lungs and fester over time.
In New Delhi, levels of PM10 — particulate matter that is 10 micrometers in size — touched 400 micrograms per cubic meter last winter. That’s four times the city’s legal limit of 100, and well above the World Health Organisation’s recommended limit of 20.
While the Chinese capital acts aggressively on high pollution days — closing schools and factories and taking government vehicles off the road — India doesn’t have a warning mechanism and until a few years ago the matter was hardly ever discussed.
The index will measure levels of PM10 and the even tinier PM2.5 as well six other indicators, including lead, ammonia, carbon monoxide and nitrogen oxide, and then calculate overall pollution. The warning levels would be colour-coded and come with specific health warnings that could be easily understood by lay people, Javadekar said.
The index will be up for review on the ministry’s website for 45 days to seek public opinion before it is functional.
Advocacy and research group Center for Science and Environment lauded the announcement but said in a statement that the measure needed to be rolled out quickly to protect public health.